[R] transforming data based on factors in a dataframe

Hello R-help list, I would really appreciate help with my factoring problem. My generated data is this: df <- expand.grid(T=seq(10,80, by=5), conc=rep(c(1, 3, 7), 2)) df$curve <- as.factor(rep(1:6, each=length(seq(10,80, by=5 df$counts <- 3*df$T/df$conc + rnorm(df$T,0,2) plot(counts~T, df)

[R] How can I slightly offset plots?

Dear R help contributers, I have several x,y scatter plots and I would like to plot them slightly offset, similar to: http://www.mathworks.com/matlabcentral/fx_files/24368/2/content/style4.jpg I've looked all over for this answer with no luck. Just a function name or previous example would probab